This invention relates to heat laminating devices and particularly to a device for use in one-sided or single-sided lamination.
In many applications it is desirable to heat laminate a clear plastic protector film to an unprotected underlying sheet for protecting the text material, etc., on the underlying sheet. The underlying sheet is referred to as the product, and the laminated product (i.e., sheet and film) is referred to as the web. The web is subsequently cut into individual pages, covers, etc.
The protector film can be applied to both sides of the underlying or unprotected product in order to protect text on both sides of the product and to offset the shrinkage of one protector film on one side with the shrinkage of the protector film on the other side. In other words, by laminating on both sides, the various forces are balanced or offset and the resulting web (i.e., product and film) is substantially planar or flat.
However, in some applications it is only necessary to protect one side of a product and only one protector film need be laminated to the product. Until now, such one-sided heat lamination has resulted in an initial curl on the laminating film side, resulting from shrinkage, etc., of the laminating film. This initial curl is undesirable and it is desirable that the laminated product be substantially flat or even have a slight reverse curl. The initial curl has resulted in products that are not as desirable as the two-sided laminations and/or in selecting more expensive alternatives.
It is an object of this invention to provide a device for use in producing one-sided laminates that are substantially flat or even have a slight reverse curl.
It is another object to provide a one-side laminating device as an attachment for existing laminating machines.
These and other objects of this invention will be apparent from the following description and appended claims.